Electrical penetrant structure

ABSTRACT

An electrical penetrant structure to provide medium voltage power penetration through a wall such as the concrete containment wall of a nuclear powered electrical generating facility and used typically to supply electrical power to electrical motor driven reactor coolant pumps. The electrical penetrant structure includes at least one conductor so mounted as to allow longitudinal and lateral movement thereof relative to its support, such longitudinal movement resulting from a thermal effect in the conductor as occurs during starting up of the pumps when the conductor handles a higher starting current than during normal pump-operating conditions, and such lateral movement being possible from a short circuit which produces high lateral forces between conductors where more than one conductor is included in the structure as is usually the case.

United States Patent [191 Fisher et a1,

[ Dec, 24, 1974 ElLEQTRlCAL PENETRANT STRUCTURE [73] Assignee: ConanCorporation, Buffalo, NY.

[22] Filed: June 30, 1972 [21] Appl. No.: 267,971

[52] lU.S. (ll. 174/151, 174/11 R, 174/12 Bl-I,

174/152 R [51] Int. Cl. G21c 13/04, I-IOlb 17/30 [58] Field of Search174/11 R, 11 RH, 12 R,

174/12 BH, 18,151, 152 R, 152 E, 152 GM 1,206,564 9/1970 Great Britain174/152 R Primary ExaminerLaramie E. Askin Attorney, Agent, orFirm-Sommer & Sommer [57] ABSTRACT An electrical penetrant structure toprovide medium voltage power penetration through a wall such as theconcrete containment wall of a nuclear powered electrical generatingfacility and used typically to supply electrical power to electricalmotor driven reactor coolant pumps. The electrical penetrant structureincludes at least one conductor so mounted as to allow longitudinal andlateral movement thereof relative to its support, such longitudinalmovement resulting from a thermal effect in the conductor as occursduring starting up of the pumps when the conductor handles a higherstarting current than during normal pumpoperating conditions, and suchlateral movement being possible from a short circuit which produces highlateral forces between conductors where more than one conductor isincluded in the structure as is usually the case.

13 Claims, 7 Drawing Figures PATEYH] UEEZNIQM sum 3 OF ELECTRICALPENETRANT STRUCTURE BACKGROUND OF THE INVENTION In nuclear poweredelectrical generating facilities, pumps are provided for circulatingreactor coolant. These pumps are driven by electrical motors of theinduction type carrying normal loads of 300 to 700 amperes atapproximately to 1'0 kilovolts. Provision must be made in the electricalsupply for such motors for the handling of a much higher current duringstart-up. It takes about seconds for the motors to come up to speed,drawing initially a current as high as 10,000 amperes which graduallydecreases to the aforementioned normal operating level of 300 to 700amperes. The conductors handling such a range of current are madeoversize, typically of copper rod having a one inch diameter, to reduceJoule or resistive heating which must be controlled within prescribedlimits during normal running of the pump drive motors, such as a F.differential from ambient at the interface between a concrete wall and ametal pipe extending therethrough on which the electrical penetrantstructure is mounted. However, there is'a substantial dimensional changeor growth in the conductor during start-up conditions when handling themuch higher current. This thermal change during motor start-up maytypically cause a conductor longitudinal growth of one-eighth inch.

Where two or more such conductors are within reasonably close proximityof each other such as several inches and should a short circuittherebetween occur, high forces are developed which cause spreading ofor tend to urge relative lateral movement between such conductors. Acurrent as high as 70,000 r.m.s. amperes may be involved in such a shortcircuit.

The reactor coolant pumps and their motors are contained on one side ofa concrete wall which is typically 4 feet thick. It is through thisconcrete wall that the electrical power supply for all conditions mustpass. Moreover, the electrical penetrant structure must be constructedand mounted on the concrete wall so that no gas can leak through thewall as a result of the electrical supply structure penetrating the sameand this is determined by using a monitoring gas.

SUMMARY OF THE INVENTION It is therefore the primary object of thepresent invention to provide an electrical penetrant structure, suitablefor electrical power supply for the purposes described and in theenvironment mentioned hereinabove which allows for longitudinal movementof the conductor during thermally induced dimensional change, and alsolateral movement of the conductor as may occur during a short circuit,while maintaining seal integrity against gas leakage.

Another object of the present invention is to provide such an electricalpenetrant structure which permits replaceability in the field of anindividual conductor, even though the whole structure is initiallyinstalled as a unit.

Yet another object of the present invention is to provide such anelectrical penetrant structure in which lateral movement of conductors,where there are at least two, is restrained.

In accordance with the present invention, an electrical penetrantstructure termination arrangement is provided comprising a wall memberhaving an opening therethrough, a conductor extending through saidopening, and means mounting said conductor on said wall member so as toallow longitudinal and lateral movement of said conductor relative tosaid wall member including a tubular sleeve of electrical insulatingmaterial surrounding said conductor and having inner and outer endportions, said inner end portion being arranged adjacent said opening inspaced relation to said wall member to provide an annular spacetherebetween, first seal means sealingly connected to said wall memberand sleeve and closing said space and allowing longitudinal and lateralmovement of said sleeve relative to said wall member, and second sealmeans sealingly connecting said outer end portion to said conductor.

Other objects and advatages of the present invention will be apparentfrom the following detailed description of a preferred embodimentillustrated in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. I is a generally central longitudinalsectional view through an electrical penetrant structure embodying thepresent invention and showing the same mounted on a concrete wall,portions of the structure and wall being broken away to reduce thelength of the figure.

FIG. 2 is a side elevational view of one of the conductor assembliesshown in FIG. 1, with portions of the assembly broken away, again toreduce the length of the figure! FIG. 3 is an enlarged fragmentarycentral longitudinal sectional view through a portion of the structureillustrated in FIG. I and showing the means for mounting a conductorassembly on a wall member, this view being taken generally on line 33 ofFIG. 1.

FIG. 4 is an enlarged vertical transverse sectional view of one of theconductor assemblies as arranged in the electrical penetrant structure,this view being taken on line 44 of FIG. 1.

FIG. 5 is a vertical transverse sectional view of the structure shown inFIG. 1, this view being taken generally on line 5-5 of FIG. 1.

FIG. 6 is an enlarged fragmentary view of the upper portion of the rightend head shown in FIG. I and showing the mounting of a monitoring ring.

FIG. 7 is an enlarged fragmentary sectional view of the lower portion ofthe left end head shown in FIG. 1 and showing the passages provided insuch end head for the introduction, removal and pressure sensing of amonitoring gas confined within the canister portion of the structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT The electrical penetrantstructure embodying the present invention is represented generally bythe numeral 10 (FIG. I), and is shown as mounted on a concrete wall IIIwhich forms part of a nuclear reactor facility. Wall 11 is shown ashaving an opening through which extends a length of cylindrical metalpipe 12, known as a nozzle, so as to be sealingly mounted on the walland having portions extending outwardly from opposite vertical surfacesthereof.

Arranged within nozzle 12 and extending therethrough is the electricalpenetrant structure 10. The same is shown as comprising a canisterincluding a cyens 21 lindrical tubular body or shell 13 having at itsleft end a header plate or end head 14' and at its right end anotherheader plate or end head 15.l3lectrical conductor assemblies 16-extendthrough the canister so provided'. While any'suitable' number of suchassemblies may be provided, in the embodiment illustrated in thedrawings six such conductor assemblies are shown as arranged inequidistant circumferentially spaced fashion. For this purpose, left endhead 14 is provided with six similar horizontal through holes 17.Similar and registering holes 18 are provided in right end head 15.

The detailed description of a single conductor assembly 16 mounted in apair of registered holes 17 and 18 will be given and is intended toapply to each of the other conductor assemblies shown in the embodimentillustrated. Also, inasmuch as the mounting of various elements issimilar on each end head, the mounting of only one set of elements onone end head, specifically the left end' head 14 will be given, with theintention that such description shall be applicable to the mounting atthe other end of such conductor assembly 16 on end wall 15. v I Similarreference numerals indicate like parts in the several figures of thedrawings. I

Referring to FIG. .3, the .openingl7 in end head 14 is shown as beinginternally threaded and of uniform diameter throughout'its length exceptfor a slight coun- V terbore 19'at its outer or left end in'which anannular seal ring such as anelastomeric O-ring 20is arranged I for apurpose hereinafter explained.

. Mounted on the inner or right end portion of inter- ,nally threadedhole 17 is a tubular adapter 21 made of tends from adapter 21 on endwall 14 to'the similar adapter on the other end wall 15. Intermediateits length, each pipe 24 is'supported on a spacer plate 25 extendingvertically transversely of the canister shell 13. The various pipes 24pass through individual holes provided in this plate 25 and are suitablywelded thereto as indicated typically at 26.

The parallel pipes 24 with their common transverse intermediate supportplate 25 are fabricated as a subassembly. Each end head 14 and Y15 withits adapters 21 mounted on the-inside thereof and welded in place arealso fabricated as separate sub-assemblies. The ends of pipes 24 slideinto the bores 23 of the respective adapt- Left end head 14 is shown ashaving a shoulder 28 adapted to be overlapped by the left marginal endportion of canister-shell 13. This shell at its left end is then securedto end head 14 by an annular weldment indicated at 29. Rightend head 15is shown as provided gether by an annular weldment indicated at 33. Thisweldment is performed at the nuclear reactor facility.

At its front end canister shell 13 is supported in radially spacedrelation to the surrounding nozzle 12 by a ring 34, suitably secured tothis shell by an annular weldment indicated at 35 and also suitablysecured to this nozzle by an annular weldment indicated at 36. Weldments35 and 36 are also applied at the nuclear reactor facility when mountingthe electrical penetrant structure on nozzle 12.

Referring to FIG. 2, the conductor assembly 16 includes a conductor 39which is shown as being an elongated cylindrical rod of conductive metalsuch as copper and surrounded by a sheath or covering of insulatingmaterial 40 of suitable composition. The insulating sheath 40 is not aslong as conductor 39 so as to provide an end face 41 for the insulationat each end from which a bare or uncovered portion 42 of the conductorextends axially. A conductor assembly 16 is arranged within and extendsthrough each of the conduit pipes 24. In order to support such assemblycoaxially in its pipe in radially spaced-relation thereto, the assemblyis provided with a plurality of longitudinally spaced sleeves 37 made ofsuitable insulating material and arranged at intervals along the lengthof the conductor sheath 40. These sleeves 37 internally closely fitsheath 40 and externally closely fit the corresponding pipe 24. Awrapping of insulating tape 38 on opposite sides of each sleeve 37secures the same to sheath 40 and holds the sleeve in the desired axiallocation on the sheath.

suitable electrical insulating material and surrounding the conductorassembly 16 with its insulating sheath 40 in slightly radially spacedrelation thereto, such radial spacing being indicated at 44. Bushing 43has a cylindrical inner end portion 45,.and a cylindrical outer endportion46 the outer corner of which is provided with an annular bevelindicated at 48. Intermediate cylindrical portions 45 and 46, bushing43is shown as provided with a series of longitudinally spaced outwardlyextending annular ribs 49 so as to provide the bushing with anexternally fluted configuration. Bushing 43 is preferably made of aceramic material such as alumina formed into a rigid element. Also, theexternal surface of the fluted intermediate portion of bushing 43 ispreferably glazed to provide a smooth, moisture-impervious, surfacewhich also discourages the collection of dust thereon.

Inner end portion 45 of bushing 43 is surrounded by a tubular housingrepresented generally by the numeral 50. This housing is shown as havingan externally threaded neck portion 51 which screws into the outerportion of internally threaded hole 17 in left end head 14. At 'itsinnerend this neck has an integral inturned of round to permit theapplication of a turning tool such as a wrench (not shown) to screwhousing 56 into hole 17. Thus, when housing 50 is screwed tightly intoopening 17, so as to compress seal ring 211, the external joint betweenhousing 50 and end head 14 is effectively sealed.

Housing 58 adjacent its outer end is shown as provided with an enlargedrecess portion indicated at 55 in which are arranged flexibleimperforate seal means represented generally by the numeral 56. Suchmeans 56 is sealingly interposed between housing 51) and inner endportion 45 of ceramic bushing 43 and is so constructed as to allowlongitudinal and radial movement of this bushing relative to thishousing. As shown, means 56 is a fexible imperforate corrugated metaltube of bellows-like construction housed within recess 55 and having atubular annular flange 58 at its inner end and another tubular annularflange 59 of larger diameter at its outer end. Flange 59 is suitablysealingly secured to housing 50 as by an annular weldment indicated at60. The portion 45 of bushing 43 surrounded by inner flange 58 issuitably metalized according to a known technique so as to permit thisflange to be brazed to bushing 43, such brazing also providing a sealedjoint and being suggested by the annular weldment indicated at 61.

lt is pointed out that the bore of tubular housing 50 inwardly ofweldment 61 is of such diameter as to leave an annular radial clearanceindicated at 62. Flange 52 of housing 50 is shown as. overlapping butslightly spaced from the inner end face of bushing 43 to provide anaxial clearance 57. A tubular spacer 63 is shown as abuttinglyinterposed between housing flange 52 and the adjacent end face ofconduit pipe 24. This spacer serves to position this conduit piperelative to the adapted 21 insofar as its longitudinal position isconcerned.

Means are provided for sealingly connecting the outer end portion 46 ofceramic bushing 43 to the conductor assembly 16. Such means is shown asincluding a metal gland body 64 having an externally cylindricalcup-shaped inner end portion 67 which is received in a counterboredportion 65 of bushing 43. Inner end portion 67 of gland body 64 is shownas having a cylindrical recess defined by a cylindrical inner wall66'and a transverse bottom wall of annular configuration 68. Theadjacent end portion of insulation sheath 41) is adapted to be receivedin this recess so that end face 41 of this sheath bears against therecess end face 68 and cylindrical surface 66 closely surrounds theexternal periphery of the sheath.

To the left or outwardly of the aforementioned recess in gland body 64,this body is provided with a cylindrical bore 69 through which the baredconductor end portion 42 extends. Outwardly of this bore 69 is anannular seat 70 of outwardly enlarging tapered configuration terminatingat its outer end in an internally threaded bore portion 71. Arrangedagainst annular seat 76 is a ferrule 72 backed up by an annular follower73, the interface between these elements being preferably spherical. Atubular compression cap 74 surrounds conductor 39 and has an externallythreaded neck 75 with an end face 76 at its inner end which bearsagainst follower 73. By screwing cap 74 into recess 71, ferrule 72 isforced against seat 70 and compressed radially inwardly to provide asealed joint with the external periphery of the bared conductor portion42. ln this manner a sealed joint between the bared or uncovered endportion 42 of conductor 39 and gland body 64 is provided.

The joint between the cylindrical inner part 67 of gland body 64 andouter end portion 46 of bushing 43 is provided by an annular U-shapedimperforate inner metal ring 78 and an annular substantially flatimperforate outer metal ring 79. Ring 78 is arranged on and surroundsthe cylindrical periphery of gland body portion 67 so that the openingof this U-shaped ring faces to the left, leaving an exposed rim or edgeon the inner leg of this ring. This inner leg is secured to gland body64 by an annular weldment indicated at 811. The rim of the other leg ofthis U-shaped ring 78 is secured to the left end of ring 79 by anannular weldment indicated at 81. The inner end portion of ring 79 has aslightly radially outwardly flared portion 82 which overlies taperedportion 48 on ceramic bushing 43. This tapered portion 48 is metalizedand the portion 82 of ring 79 is brazed thereto, such brazing beingsuggested by the annular weldment indicated at 83. Thus, the jointbetween bushing 43 and bland body 64 is effectively sealed, by rings 78and 79 and weldments 80, 81 and 83.

From the foregoing, it will be seen that the outer seal means sealinglyconnects the outer end of ceramic bushing 43 to conductor 39 in suchmanner that this bushing is constrained to move with this conductorduring any longitudinal movement thereof, and the inner seal meanssealingly connects the inner end of this bushing to end head 14 in suchmanner that both longitudinal and lateral movement of this conductorrelative to this end head is permitted. It is the bellows-like tube 56which is so structured as to be expandable and contractible axially topermit such relative longitudinal movement, and also to be flexiblelaterally or radially so that one end thereof can move radially relativeto the opposite end and thereby permit such lateral movement of theconductor relative to the end head. The clearance 62 allows relativeradial movement between bushing 43 and housing 50. The clearance 44allows some relative radial movement between insulation sheath 411 andbushing 43.

The canister provided by shell 13 and end heads 14 and 15 define achamber 84 which is filled with a gas under pressure, such as nitrogenmaintained at the pressure of about 15 pounds per square inch gauge.This gas is maintained within chamber 84 for the purpose of monitoringany leakage along any of the joints provided by the aforementioned innerand outer seal means involved with the mounting of conductor assemblies16 on end heads 14 and 15, and also for the pur pose of monitoring anyleakage due to the mounting of the canister on nozzle 12.

As to the mounting of this canister on this nozzle, an annularmonitoring ring 85 having an inner annular groove 86 is shown assurrounding weldment 33 between right end head 15 and nozzle 12. Ring 85is shown as secured to end head 15 by an annular weldment 88 and tonozzle 12 by an annular weldment 89. This ring has a radial hole 90 towhich a tube (not shown) can be suitably attached and associated withsuitable apparatus (not shown) for monitoring gas that is collected ingroove 86 as a result of any leakage outwardly through the jointsprovided by weldments 33 and 31.

Canister chamber 84 is filled, serviced and the pressure thereinmonitored by utilizing a passage 91 ex tending axially through left endwall 14 and the radial branch passage 92 leading from passage 91 to theperiphery of this end head. The outer end of passage 91 is shown asbeing closed by a plug 93. The outer end of branch passage 92 is shownas being connected to fitting 94 for a tubing 95 which leads to remotemonitoring equipment (not shown). Suitable gauges, filling and drainvalves, none of which is shown, can be connected to the outer ends ofpassages 91 and 92, as desired in order to fill, maintain and measurethe pressure of the monitoring gas confined within canister compartment84.

The exposed outer end portion 42 or conductor 39 of each assembly 16 ateach end thereof is shown as provided with a suitable connector 96 towhich a suitable conductive lead (not shown) in turn may be connected.These connectors 96 are shown as being of the clamp type so as to becapable of being mounted on and removed from the conductors. The exposedouter end portions 42 of the variousconductors may have differentlengths as shown to allow for mounting of the connectors thereon atdifferent axial locations to avoid interference with one another.

. At each end of the electrical penetrant structure, the leads (notshown) for connectors 96 severally have a shield. The ends of theseshields adjacent each end of the electrical penetrant structure arejoined together and electrically connected to an electrical connector101 mounted on corresponding end head 14 or 15 so as to be insulatedtherefrom. These connectors are electrically connected togetherinternally of the canister so that such shields extend electricallytherethrough. The conductor portion of connector 101 is normally a 600volt capacity conductor.

As previously explained, in case of a short circuit, especially onebetween two adjacent conductors 39, high level forces would be developedtending to move the conductors laterally relative to each other. Thispossibility is minimized in two ways. One way is to physically connectadjacent conductor bars 39 to restrain their relative movement. For thispurpose, a strap such as indicated at 100 is suitably clamped atopposite ends to the exposed portions 42 of adjacent conductors. Ifthese conductors are not to be connected in parallel, this strap is madeof suitable insulating material. On the other hand, if the conductorsare to be connected in parallel, this strap can be made of a conductivemetal such as copper so as to provide a buss strap.

The second way of minimizing relative lateral movement between adjacentconductors 39 is by providing a short circuit path to ground rather thanfrom one conductor to another. Accordingly, conductive pipe 24,surrounding each conductor assembly 16, at its opposite ends iselectrically connected through adapters 21 to end walls 14 and 15 whichare at ground potential. Inasmuch as these end walls are electricallyconnected to ground, in the event of a short circuit the path of theshort circuit is likely to be from the affected conductor 39 to thesurrounding pipe 24, to end heads 14 and 15 and thence to ground. Thiswill prevent a shortcircuiting of one conductor to another conductor.

In the use for the invention as explained, the reactor coolant pumpsoperate on a resistive grounded system so that in the event of the shortcircuit of one of the conductors 39 to ground within the assembly thenormal rating of the conductor will not be exceeded. As a consequence,the whole assembly is still protected.

Regarding strap between adjacent conductors, regardless of whether suchstrap is made of a conductive or non-conductive material, it has theadvantage of stabilizing the assembly of conductors 39 and restrainingthem from relative lateral movement. Apart from forces that might begenerated during short circuits to cause lateral movement of a conductorrelative to the end heads, the electrical penetrant structure istypically so dimensioned that there is more length of a conductor insidethe canister than outside. Hence the conductor tends to fulcrum on theend heads. The tie straps 100 reduce this tendency and improvestability.

In the event a conductor 39 is desired to be replaced in the electricalpenetrant structure after installation, this can be readily done in thefield in the following manner. Connectors 96 and straps 100 on theconductor 39 to be replaced are removed. Next, compression cap 74 isunscrewed from the gland body 64 at each end of such conductor, therebyfreeing up ferrule 72 for removal of it and its follower 73 at each end.Bushing 43 at each end is then removed from the corresponding end head14 or 15 by unscrewing the corresponding housing 50, being careful toturn the housing and bushing together so as not to break seal means 56.This conductor is then pulled axially from the structure. A replacementconductor is inserted in the structure, the bushing 43 with attachedhousing 50 are mounted over each end of the replacement conductor andthe housing screwed to the end head, and the ferrules 72, followers 73and caps 74 are then replaced and tightened. The connectors 96 andstraps 100 can then be mounted on the exposed ends of replacementconductor. It is to be noted that none of the welded or brazed sealjoints is disturbed.

It will thus be seen that the embodiment of the present inventionillustrated and described accomplishes the various stated objects.

What is claimed is:

1. In an electrical penetrant structure, the combination comprising awall member having an opening therethrough, a conductor extendingthrough said opening, and means mounting said conductor on said wallmember so as to allow longitudinal and lateral movement of saidconductor relative to said wall member including a tubular sleeve ofrigid electrical insulating material surrounding said conductor andhaving inner and outer end portions, said inner end portion beingarranged adjacent said opening in spaced relation to said wall member toprovide an annular space therebetween, first seal means sealinglyconnected to said wall member and sleeve and closing said space andallowing longitudinal and lateral movement of said sleeve relative tosaid wall member, and second seal means sealingly rigidly connectingsaid outer end portion to said conductor.

2. An electrical penetrant structure according to claim 1 wherein saidfirst seal means includes a flexible imperforate corrugated tube one endof which is sealingly connected to said wall member and the other end ofwhich is sealingly connected to said sleeve, and said second seal meansremovably connects said sleeve to said conductor.

3. An electrical penetrant structure according to claim 2 wherein saidopening in said wall member is internally threaded, said first sealmeans includes a tubular housing surrounding said sleeve and externallythreaded and removably screwed into said threaded opening and having anenlarged head, a seal ring between said head and wall member and sealingthe threaded joint between said wall member and housing, and said oneend of said tube is sealingly connected to said housing.

4-. An electrical penetrant structure according to claim 3 wherein saidenlarged head is internally recessed, and said flexible corrugated tubeis arranged in such housing recess.

5. An electrical penetrant structure according to claim 1 wherein saidsecond seal means includes a gland body surrounding said conductor andarranged partially within said sleeve, ferrule means arranged withinsaid gland body and surrounding said conductor, a compression capconnected to said gland body and arranged to compress said ferrulemeans, and an imperforate ring means sealing the joint between saidsleeve and gland body.

6. An electrical penetrant structure according to claim 5 wherein saidgland body is made of metal, said ring means is brazed to said glandbody and to said sleeve.

7. An electrical penetrant structure according to claim 5 wherein saidopening in said wall member is internally threaded, said first sealmeans includes a tubular housing surrounding said sleeve and externallythreaded and removably screwed into said threaded opening and having anenlarged head internally recessed, a seal ring between said head andwall member and sealing the threaded joint between said wall member andhousing, said first seal means also including a flexible imperforatecorrugated tube arranged in such housing recess and having one endsealingly connected to said housing and its other end sealinglyconnected to said sleeve.

8. An electrical penetrant structure according to claim 7 wherein thereis a second conductor extending through a second opening in said wallmember and mounted thereon in the same 'manner as defined for the firstmentioned conductor, that portion of each of said conductors arranged onthe inside of said wall member being surrounded in spaced relation by anelectrically conductive pipe electrically connected to said, and meansmounted on said wall member for grounding said wall member.

9. An electrical penetrant structure according to claim ll wherein thereis a second conductor extending through a second opening in said wallmember and mounted thereon in the same manner as defined for the firstmentioned conductor, such conductors severally extending outwardlybeyond their respective second seal means, and strap meansinterconnecting such extended portions of said conductors to restrainrelative lateral movement between said conductors.

l0. An electrical penetrant structure according to claim 9 wherein saidstrap means is made of a conductive material so as to provide a bussstrap electrically connecting said conductors in parallel.

111. An electrical penetrant structure according to claim 9 wherein saidstrap means is made of an electrical insulating material.

12. An electrical penetrant structure providing electrical powertransmission in the 5 to 10 kilovolt range through the containment wallof a nuclear powered electrical generating facility, comprising acanister extending through said wall and including spaced end headshaving openings therethrough, an uninterrupted solid conductor extendingthrough said openings, and means insulatively and sealingly mountingsaid conduc tor on said end heads so as to allow longitudinal andlateral movement of said conductor relative to said end heads.

13. An electrical penetrant structure according to claim 112 whereinsuch mounting means are removably connected to said conductor and alsoto said end heads thereby to allow replacement of said conductor as wellas said means following permanent installation of said canister to saidcontainment wall.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent No3,856,983 Dated December 24, 1974 Edward Fisher, Wilbur S Ratio RomanJankowiak, et al Inventor) It in certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 5, line 36: "adapted" should be-adapter-; Col.- 6, line 22: "bland"should be-gland-;- Col. 7, line 13: "or" should be-of--; I Col. 8, line32: between. "of" and "replacement",-the--= should be inserted; Claim 8,line 8: between "said" and ,and" ,.-wall membershould be inserted Signedand sealed this 6th day of May 1975.

(SEAL) 1 Attest: I

' C. MARSHALL DANN RUTH C. MASON Commissioner of. Patents AttestingOfficer and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION :3 Patent 3,856,983 Dated December 24, 1974 Edward Fisher,Wilbur S. Ratio, Roman Jankowiak, et al. Inventofls) It is certifiedthat: error appears in the above-identified patent and that said Letter:Patent are hereby corrected ee shown below:

Col. 5, line 36: "adapted" should be-adapter--; Col.-' 6, line 22:"bland" should be-gland--;- Col. 7, line 13: "or" should be-of---; Col.8, line 32: betweenv "of" and "replacement",-theshould be inserted;

Claim l between d", and ,and" Wall member-- should be inserted Signedandseled rhis 6th day of May 1975.

(SE Attest:

' e C. MARSHALL DANN RUTH C. MASON I Commissioner of. Patents AttestingOfficer and Trademarks

1. In an electrical penetrant structure, the combination comprising awall member having an opening therethrough, a conductor extendingthrough said opening, and means mounting said conductor on said wallmember so as to allow longitudinal and lateral movement of saidconductor relative to said wall member including a tubular sleeve ofrigid electrical insulating material surrounding said conductor andhaving inner and outer end portions, said inner end portion beingarranged adjacent said opening in spaced relation to said wall member toprovide an annular space therebetween, first seal means sealinglyconnected to said wall member and sleeve and closing sAid space andallowing longitudinal and lateral movement of said sleeve relative tosaid wall member, and second seal means sealingly rigidly connectingsaid outer end portion to said conductor.
 2. An electrical penetrantstructure according to claim 1 wherein said first seal means includes aflexible imperforate corrugated tube one end of which is sealinglyconnected to said wall member and the other end of which is sealinglyconnected to said sleeve, and said second seal means removably connectssaid sleeve to said conductor.
 3. An electrical penetrant structureaccording to claim 2 wherein said opening in said wall member isinternally threaded, said first seal means includes a tubular housingsurrounding said sleeve and externally threaded and removably screwedinto said threaded opening and having an enlarged head, a seal ringbetween said head and wall member and sealing the threaded joint betweensaid wall member and housing, and said one end of said tube is sealinglyconnected to said housing.
 4. An electrical penetrant structureaccording to claim 3 wherein said enlarged head is internally recessed,and said flexible corrugated tube is arranged in such housing recess. 5.An electrical penetrant structure according to claim 1 wherein saidsecond seal means includes a gland body surrounding said conductor andarranged partially within said sleeve, ferrule means arranged withinsaid gland body and surrounding said conductor, a compression capconnected to said gland body and arranged to compress said ferrulemeans, and an imperforate ring means sealing the joint between saidsleeve and gland body.
 6. An electrical penetrant structure according toclaim 5 wherein said gland body is made of metal, said ring means isbrazed to said gland body and to said sleeve.
 7. An electrical penetrantstructure according to claim 5 wherein said opening in said wall memberis internally threaded, said first seal means includes a tubular housingsurrounding said sleeve and externally threaded and removably screwedinto said threaded opening and having an enlarged head internallyrecessed, a seal ring between said head and wall member and sealing thethreaded joint between said wall member and housing, said first sealmeans also including a flexible imperforate corrugated tube arranged insuch housing recess and having one end sealingly connected to saidhousing and its other end sealingly connected to said sleeve.
 8. Anelectrical penetrant structure according to claim 7 wherein there is asecond conductor extending through a second opening in said wall memberand mounted thereon in the same manner as defined for the firstmentioned conductor, that portion of each of said conductors arranged onthe inside of said wall member being surrounded in spaced relation by anelectrically conductive pipe electrically connected to said, and meansmounted on said wall member for grounding said wall member.
 9. Anelectrical penetrant structure according to claim 1 wherein there is asecond conductor extending through a second opening in said wall memberand mounted thereon in the same manner as defined for the firstmentioned conductor, such conductors severally extending outwardlybeyond their respective second seal means, and strap meansinterconnecting such extended portions of said conductors to restrainrelative lateral movement between said conductors.
 10. An electricalpenetrant structure according to claim 9 wherein said strap means ismade of a conductive material so as to provide a buss strap electricallyconnecting said conductors in parallel.
 11. An electrical penetrantstructure according to claim 9 wherein said strap means is made of anelectrical insulating material.
 12. An electrical penetrant structureproviding electrical power transmission in the 5 to 10 kilovolt rangethrough the containment wall of a nuclear powered electrical generatingfacility, comprising a canister extending through said wall andincluding spaced end heads Having openings therethrough, anuninterrupted solid conductor extending through said openings, and meansinsulatively and sealingly mounting said conductor on said end heads soas to allow longitudinal and lateral movement of said conductor relativeto said end heads.
 13. An electrical penetrant structure according toclaim 12 wherein such mounting means are removably connected to saidconductor and also to said end heads thereby to allow replacement ofsaid conductor as well as said means following permanent installation ofsaid canister to said containment wall.